Backflow Prevention Flashcards
7 cards from real Journeyman Plumbers Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Backflow Prevention flashcards as text
An RPZ assembly must be installed how far above the floor or ground to allow for drainage and testing?
Answer: At least 12 inches
RPZ assemblies require a minimum of 12 inches of clearance above the floor to allow access for testing and to permit relief port drainage.
Which backflow device is NOT acceptable for use under continuous supply pressure?
Answer: Atmospheric vacuum breaker (AVB)
Atmospheric vacuum breakers must not be subjected to continuous supply pressure exceeding 12 hours as it can hold the check open, defeating the device.
What does the relief port on an RPZ assembly do during a backflow event?
Answer: It opens to discharge water and protect the supply line from contamination
When the differential pressure drops below 2 psi, the relief valve opens to atmosphere, discharging water rather than allowing contaminated water to reach the supply.
A plumber is installing a backflow preventer on a chemical injection system for a swimming pool. Which device is required?
Answer: Reduced pressure zone assembly
Chemical injection systems represent a severe health hazard and require an RPZ assembly for the highest level of protection.
How often must a testable backflow prevention assembly be tested after installation?
Answer: Annually
Most jurisdictions following the USC model require testable backflow prevention assemblies to be tested annually by a certified tester.
Which of the following is an example of a high-hazard cross-connection?
Answer: A carbonated beverage dispenser connected to potable water
Carbonated beverage dispensers create a high-hazard cross-connection because CO2 and syrup can be siphoned back into the potable supply.
What is the purpose of the bypass valve on a backflow preventer assembly installed in a commercial building?
Answer: To allow water to flow while the assembly is being tested or repaired
A bypass with a backflow preventer allows the building to maintain water service while the primary assembly is taken offline for testing or maintenance.